Communication method, user terminal and processor

Abstract

A communication method according to an embodiment comprises: a step of performing, by a user terminal, a reselection of a target cell to be used as a serving cell from among a plurality of cells operated at different frequencies. The step of performing the reselection of the target cell comprises: a first reselection step of performing, by the user terminal, the reselection of the target cell in a response to reception of a paging signal for requesting the reselection of the target cell from a current serving cell; and a second reselection step of performing, by the user terminal, the reselection of the target cell in a response to a trigger without dependence on the paging signal. In the first reselection step, the user terminal starts measurement of a quality of a measurement target frequency included in system information broadcast from the current serving cell, in response to the reception of the paging signal.

The invention claimed is: 
     
       1. A communication method, comprising:
 receiving, by a user terminal, from a current serving cell of the user terminal, system information indicating frequencies different from a frequency of the current serving cell, the system information being broadcast from the current serving cell; 
 receiving, by the user terminal, from the current serving cell, a paging signal including a request message requesting the user terminal to perform cell reselection in which the user terminal reselects a target cell to be used as a serving cell, the paging signal being different from the system information; and 
 performing the cell reselection, by the user terminal, in response to receiving the paging signal including the request message, wherein 
 performing the cell reselection comprises:
 measuring, by the user terminal, quality of the frequencies included in the system information received from the current serving cell, in response to receiving the paging signal including the request message; and 
 reselecting, by the user terminal, the target cell to be used as the serving cell based on a result of the measuring. 
 
 
     
     
       2. The communication method according to  claim 1 , wherein
 in performing the cell reselection, the user terminal performs the reselection of the target cell by use of an identifier of the user terminal. 
 
     
     
       3. The communication method according to  claim 1 , wherein
 in performing the cell reselection, the user terminal performs the reselection of the target cell from a plurality of cells having a quality that satisfies a predetermined quality criterion. 
 
     
     
       4. The communication method according to  claim 1 , wherein
 in the measuring, the user terminal measures quality of the frequencies included in the system information even if a quality of the current serving cell satisfies a predetermined quality criteria. 
 
     
     
       5. The communication method according to  claim 1 , wherein
 in performing the cell reselection, the user terminal reselects the target cell from two or more candidate cells if the two or more candidate cells have the same priority. 
 
     
     
       6. The communication method according to  claim 1 , wherein
 the paging signal is transmitted from the current serving cell at a paging cycle assigned to the user terminal. 
 
     
     
       7. The communication method according to  claim 1 , wherein
 in performing the cell reselection, the user terminal performs the cell reselection in response to receiving the paging signal including the request message regardless of whether a quality of the current serving cell satisfies a predetermined quality criterion. 
 
     
     
       8. The communication method according to  claim 1 , wherein
 in performing the cell reselection, the user terminal reselects the target cell based on a priority of the current serving cell and priorities of the frequencies included in the system information. 
 
     
     
       9. A user terminal, comprising
 a memory and a processor electrically connected to the memory, wherein 
 the processor is configured to execute processes of:
 receiving from a current serving cell of the user terminal, system information indicating frequencies different from a frequency of the current serving cell, the system information being broadcast from the current serving cell; 
 receiving from the current serving cell, a paging signal including a request message requesting the user terminal to perform cell reselection in which the user terminal reselects a target cell to be used as a serving cell, the paging signal being different from the system information; and 
 performing the cell reselection in response to receiving the paging signal including the request message, wherein 
 performing the cell reselection comprises: 
 measuring quality of the frequencies included in the system information received from the current serving cell, in response to receiving the paging signal including the request message; and 
 reselecting the target cell to be used as the serving cell based on a result of the measuring. 
 
 
     
     
       10. A processor for controlling a user terminal, configured to execute processes of:
 receiving from a current serving cell of the user terminal, system information indicating frequencies different from a frequency of the current serving cell, the system information being broadcast from the current serving cell; 
 receiving from the current serving cell, a paging signal including a request message requesting the user terminal to perform cell reselection in which the user terminal reselects a target cell to be used as a serving cell, the paging signal being different from the system information; and 
 performing the cell reselection in response to receiving the paging signal including the request message, wherein 
 performing the cell reselection comprises:
 measuring quality of the frequencies included in the system information received from the current serving cell, in response to receiving the paging signal including the request message; and 
 reselecting the target cell to be used as the serving cell based on a result of the measuring.